Various approaches have been proposed for the injection of liquid additives into horticultural watering systems. Of particular interest, liquid fertilizers have been injected into watering systems employed in the turf growth/maintenance industry for many years.
Known approaches for liquid fertilizer injection have included both powered and non-powered systems. By way of primary example, metering pumps have been utilized in connection with golf course watering systems around the world. Such systems have proven too expensive to implement in many applications, including for example residential sprinkler systems.
Proposed non-powered systems have included venturi-type injectors and flow-through injectors. The venturi-type injectors have had limited success due to unacceptable attendant pressure loss in the system. Flow-through injectors provide for the flow of water through a reservoir, or pot, charged with a liquid or water soluble, granulated fertilizer. Such systems generally require recharging of the reservoir upon each use. Further, the reliable obtainment of a desired fertilizer application rate has proven problematic.
More generally in the later regard, it has been recognized that the application of small dosages of fertilizer to turf or foliage over an extended time is preferable to a single high dosage application. Low dosages avoid extreme growth spurt/burning cycles, and otherwise enhance the establishment of desirable root structures. In turn, susceptibility to pest and weed infestation is significantly reduced.